The following abbreviations and terms are herewith defined, at least some of which are referred to within the following description of the present disclosure.    3GPP 3rd-Generation Partnership Project    ASIC Application Specific Integrated Circuit    BSS Base Station Subsystem    BTS Base Transceiver Station    CN Core Network    DL Downlink    DSP Digital Signal Processor    EC Extended Coverage    EC-GSM Extended Coverage Global System for Mobile Communications    eNB Evolved Node B    EDGE Enhanced Data rates for GSM Evolution    EGPRS Enhanced General Packet Radio Service    GSM Global System for Mobile Communications    GERAN GSM/EDGE Radio Access Network    GPRS General Packet Radio Service    IE Information Element    IoT Internet of Things    LLC Logical Link Control    LTE Long-Term Evolution    MME Mobility Management Entity    MPM Multilateration Positioning Method    MS Mobile Station    MTA Multilateration Timing Advance    MTC Machine Type Communications    NB-IoT Narrow Band Internet of Things    PACCH Packet Associated Control Channel    PDN Packet Data Network    PDU Protocol Data Unit    RAN Radio Access Network    RLC Radio Link Control    RRLP Radio Resource Location Services Protocol    SGSN Serving GPRS Support Node    SMLC Serving Mobile Location Center    TA Timing Advance    TBF Temporary Block Flow    TS Technical Specification    TSG Technical Specification Group    UE User Equipment    UL Uplink    WCDMA Wideband Code Division Multiple Access    WiMAX Worldwide Interoperability for Microwave Access    Extended Coverage: The general principle of extended coverage is that of using blind transmissions for the control channels and for the data channels to realize a target block error rate performance (BLER) for the channel of interest. In addition, for the data channels the use of blind transmissions assuming MCS-1 (i.e., the lowest modulation and coding scheme (MCS) supported in EGPRS today) is combined with HARQ retransmissions to realize the needed level of data transmission performance. Support for extended coverage is realized by defining different coverage classes. A different number of blind transmissions are associated with each of the coverage classes wherein extended coverage is associated with coverage classes for which multiple blind transmissions are needed (i.e., a single blind transmission is considered as the reference coverage). The number of total blind transmissions for a given coverage class can differ between different logical channels.    Timing Advance Information: Identifies the timing advance value a BSS determines to be applicable to the mobile station in the cell where it has performed the MTA procedure and is part of the MTA related measurement information passed from the BSS to the SMLC during the MTA procedure. When the RLC Data Block method or Extended Access Burst method is used for performing the MTA procedure (see 43.059 Draft Change Request (CR) (Rel-14) v13.2.0, “Introduction of Multilateration,” Source: Ericsson LM, RAN WG6 telco #1 on ePOS_GERAN, dated Dec. 15, 2016—the contents of which are hereby incorporated herein by reference for all purposes), the timing advance value estimated by the BSS may be adjusted according to the “MS Transmission Offset” value extracted from the RLC Data Block or the Extended Access Burst (see “Analysis of MS Transmission Accuracy”, Source: Ericsson LM, RAN WG6 telco #1 on ePOS_GERAN, dated Dec. 15, 2016—the contents of which are hereby incorporated herein by reference for all purposes) prior to the timing advance value being forwarded by the BSS to the SMLC. Alternatively, the “MS Transmission Offset” value may be sent to the SMLC along with the corresponding non-adjusted timing advance value wherein the SMLC is then responsible for performing the adjustment.
At the 3rd-Generation Partnership Project (3GPP) Technical Specification Group (TSG) Radio Access Network (RAN) Meeting #72, a Work Item on “Positioning Enhancements for GERAN” was approved (see RP-161260; Busan, Korea; 13-16 Jun. 2016—the contents of which are hereby incorporated herein by reference for all purposes), wherein one candidate method for realizing improved accuracy when determining the position of a mobile station (MS) is multilateration timing advance (MTA) (see RP-161034; Busan, Korea; 13-16 Jun. 2016—the contents of which are hereby incorporated herein by reference for all purposes), which relies on establishing the MS position based on Timing Advance (TA) values in multiple cells.
At the 3GPP TSG-RAN1 Meeting #86, a proposal based on a similar approach was made also to support positioning of Narrow Band Internet of Things (NB-IoT) mobiles (see R1-167426; entitled “On timing advance based multi-leg positioning for NB-IoT;” Source: Ericsson LM; Gothenburg, Sweden; 22-26 Aug. 2016—the contents of which are hereby incorporated herein by reference for all purposes). In regards to IoT devices, it expected that in a near future, the population of Cellular IoT devices will be very large. Various predictions exist; one such prediction is that there will be >60000 cellular IoT devices per square kilometer (see draft CR 43.059 entitled “Introduction of Multilateration”, Source Ericsson LM, RAN WG6 telco #1 on ePOS_GERAN, dated: Dec. 15, 2016—the contents of which are hereby incorporated herein by reference for all purposes), and another prediction is that there will be 1000000 cellular IoT devices per square kilometer (see R1-167426; entitled “On timing advance based multi-leg positioning for NB-IoT;” Source: Ericsson LM; Gothenburg, Sweden; 22-26 Aug. 2016—the contents of which are hereby incorporated herein by reference for all purposes). A large fraction of these cellular IoT devices are expected to be stationary, e.g., gas and electricity meters, vending machines, etc. . . . . Extended Coverage GSM-IoT (EC-GSM-IoT) and NB-IoT are two standards for Cellular IoT that have been specified by 3GPP TSG GERAN and TSG Radio Access Network (RAN).
Timing Advance (TA) is a measure of the propagation delay between a base transceiver station (BTS) and the MS, and since the speed by which radio waves travel is known, the distance between the BTS and the MS can be derived. Further, if the TA applicable to the MS is measured within multiple BTSs and the positions (i.e., longitude and latitude) of these BTSs are known, the position of the MS can be derived using the measured TA values. The measurement of the TA requires that the MS synchronize to each neighbor BTS and transmit a signal time-aligned with the timing of the BTS estimated by the MS. The BTS measures the time difference between its own time reference, and the timing of the received signal (transmitted by the MS). This time difference is equal to two times the propagation delay between the BTS and the MS (one propagation delay of the BTS's synchronization signal sent to the MS, plus one equal propagation delay of the signal transmitted by the MS back to the BTS).
As shown in FIG. 1 (PRIOR ART), once a set of TA values TA1, TA2, and TA3 are established using a set of one or more BTSs 1021, 1022, 1023 (only three shown) during a given positioning procedure, the position of the MS 104 can be derived through a so called Multilateration Timing Advance (MTA) procedure wherein the position of the MS 104 is determined by the intersection of a set of hyperbolic curves 1061, 1062, 1063 associated with each BTS 1021, 1022, 1023. The calculation of the position of the MS 104 is typically carried out by a serving positioning node 110 (e.g., serving Serving Mobile Location Center 110 (SMLC 110)), which implies that all of the derived TA values TA1, TA2, and TA3 and the associated position information of the BTSs 1021, 1022, 1023 needs to be sent to the serving positioning node 110 (i.e., the serving SMLC 110) which initiated the positioning procedure. In this example, the BTSs 1021, 1022, 1023 transmit their respective TA1, TA2, and TA3 to one BSS 108 which then transmits TA1, TA2, and TA3 to the SMLC 110. The BSS 108 and SMLC 110 are both connected to a SGSN 112. It should be appreciated that each BTS 1021, 1022, 1023 could also be connected to different BSSs (not shown) where in any configuration the SMLC 110 is still provided with the calculated TA1, TA2, and TA3.
At the 3GPP TSG-RANG Meeting #3, some enhancements to the procedure have been proposed wherein the Base Station System (BSS) 108 estimates with sufficient accuracy the Timing Advance value in the serving cell during the initiation of the Multilateration Timing Advance procedure. Referring to FIGS. 2A-2B (PRIOR ART), there is a signal diagram which illustrates one of the proposed enhancements for allowing the BSS 108 to estimate the Timing Advance value in the serving cell during the initiation of the Multilateration Timing Advance procedure. This proposed enhancement consists of introducing a new (EC-) Packet Channel Request message 202 in step 3 with an indication that the MS 104 is responding to a paging request for positioning 204 from step 1. This allows the BSS 108 to use more advanced Timing Advance estimation algorithms such as oversampling and interpolation during the reception of the subsequent Radio Link Control (RLC) data block 206 (last step in step 3) containing the Logical Link Control (LLC) Protocol Data Unit (PDU) 208 and mobile station accuracy information 210. At the 3GPP TSG-RANG Meeting #3 it has also been proposed (but no solutions presented) that in step 11 the BSS 108 should also be able to estimate the Timing Advance value 212 in the serving cell on reception of the (Extended Coverage-) Packet Associated Control Channel ((EC-)PACCH) Packet Downlink Ack 214. Then, the BSS 108 could send at step 12 the estimated timing advance 212 (note: the estimated timing advance 212 is adjusted according to a “MS Transmission Offset” that the BSS 108 receives from the MS 104 in the (EC-)PACCH Packet Downlink Ack 214, see the definition of “Timing Advance Information” above) along with BTS receiver accuracy and MS accuracy parameters (shown as MS accuracy information 216) to the SMLC 110 to update the serving cell related timing estimation, thereby allowing the MS 104 to leave the serving cell to perform the Multilateration Timing Advance procedure in additional cells without first performing the Multilateration Timing Advance procedure in the serving cell (note: the BTS receiver accuracy is passed to the SMLC 110 as part of the MS accuracy information 216 and is information that the BSS 108 is able to self-generate (i.e., the BTS receiver accuracy portion of the MS accuracy information 216 is not passed from the wireless device 104 to the BSS 108)). The present disclosure describes why the BSS 108 cannot perform steps 11-12 and then discloses a solution such that when implemented the BSS 108 can perform steps 11-12.